Light-dissolving device.



1. w. & K.' s. REN-KLRT; LIGHT DsoLvmGEvl'cg; APPLIATioN "man `MN, '2Lv yslg.' Y s 1,282,748. Patented oct. 2.), mlb.

i mlmluiiiiiiiiiiiiiliii 'iii www 1*. w. s. K. s. BRENKERT.

LIGHT DISSOLVING DEVICE.

APPLICATION FILED 1AN.2|. 1918.

1,282,743. Patented 0@.29,1918.,

2 shears-sum 2. H 40 tiiairifii) sra'wanr opinion Josnrn w. nnENxElvr AND KARL s. nnnNxnm, or Dn'mon, MICHIGAN.

LIGHT-DISSOLVING DEVICE.

To all whom it may concern:

Be itv known that we, JOSEPH W. BREN- KERT and 'KARL S. BRENKERT, citizens of the useful Improvements in ,Light-Dissolving Devices, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates-t0 an electric light dissolving device, and the primary object of our invention is to furnish a stereopticon or picture projecting machine with a permanent light `dissolving device to which itis only necessary to connect ordinary electric lugs to (place the device in operative con ition thus ob'viating the necessity of carrying-a separate device with the stereopticon and making proper. electrical connections. vBy making the device a fixture there lis no danger of improper electrical connectlons being made and the compactness of the device andl its location permits of the stereopticon being easily handled and the light thereof dis-l y solved as occasion requires. y

Another object of our invention, to which we attach considerable importance,.is to pro'- vide an electric device lfor controlling the relative brilliancy of two or more electric incandescent lamps, bywhich. the brilliancy' of the one v,lamp or set of lamps` may -be gradually varied-from .invisible illumination,"v

` f or vice versa, without affecting. the full bril,--

` 4tained according to the direction in which.:

the lever, or cut-out arm, is moved. All this K y that; is substantially rectangular inl plant and f comparatively at, said. casing having. the

liancyof the .other lamp orset of lamps.

This operation being reversible on either lamp or set of lamps anda likefresulty obbeingaccomplished by the movement of a single lever,` or` cut-out" arm, .whichl Yengages .alternately two lseparately wound lresistance i vmembers and twov shunt members, said shunt -.members vbeing-.placed in an alternate position from their relative resistance members.

A further [object of our invention is toprovide an vvelectric light dissolving device wherein. the parts are constructed fwith a view of reducing the cost of manufacture and at-the lsa'mejtixne retain thosefeatures by whichsafety, minimum heat, durability and ease ofassembling are-secured. With these ends in view ourinvention'resides in` the novel construction, comblnatlon and ar- Specication of Letters Patent. Application led January 21, 1918. 'serlallm 212,990.-

vice in plan;

Patented oet. 2 9, 1918.

Fig. 3'is an yenlarged.horizontal sectional view of the device Fig. Itis a" front elevationy ofthe same, showing the casing in section;

Fig.'5 is a cross the line V/-V of Fig.3, and

, F ig.' 6 is a diagrammatic view'of the elec- 'tr1cal connectlon's of the device.'

In describing ouryinvention byl aid of the views above referred to, we desire to point out that tne same are intended as 4merely `illustrative of the device as now constructed and in use,y and'we donot care toconfne our inventlon to the precise construction and arrangement of partsshown. lThe-following description is therefore to be broadly consectional view taken on strued as including such substitute construc- 'tions and arrangement of parts which are the obvious equivalent of those to be hereinafter referred to.

In the drawings, the reference numeral 1 denotes superposedv stereoptlcons or picturer projecting machines supported by upright frames Zconnectedby telescopic bellows adjusting 'rods 3` and 4. and it is 'on the stan tion'ary portions of the rods 3 thatfwesus- 'pend the lightfdissolving device; making the same a fixture under the lower stereopticon.

v v'The device .comprises ametallic casing .5

upper wall--Vthereo'f provided' with clamping members `whichmayjbe tightened on they y vProjecting inwardlyfrbm the end walls of the casing 5 are studs;8v and the inner endsA of thesevstuds support-,parallel walls 9 and 10 of insulation material,v asber. The walls 9 and 10 are connected by tie ,rods 411 and 12,

' the former 'extending through and supporting av hollowl metalllc'core' 13 inclosed by a cover 1,4 of insulation materiaLas an asbes- Vboth of which are suitab tos composition. On the insulated hollow core 13 is wound two resistance coils 15 .and 16. said coils direi-ging or having the windings thereof decreasing in size from the cen tral portion of the hollow core toward the ends thereof. The central convolutions of the coils 15 and 16 enter the hollow core 13 through a conduit 17 providedtherefor 1n the top of the core and said reslstance coils are connected to binding posts 18 and 1 9, carried by the wall 10, as best shown 1n Fig. 3.

The connecting rod 12 is provided with an upright bearing 20 insulated, as at 21, from the resistance coils. The upper and lower ends of the bearing 20 pivotally supports the rear ends of a yoke switch arm 22 and said arm has a handle 23 of insulation extending through a slot 24 in the front wall of the casing 5, so that said switch arm may be swung in a horizontal plane relative to the resistance coils 15 and 16. To permit of such movement, the hollow core 13 has the front wall thereof curved so as to provide clearance for the switch arm.

At the outer end of the switch arm is a vertical sprindle 24 having the ends thereof extending through slots 25 of the switch arm and connected thereto by coiled retractile springs 26. On the spindle 24'* is a rotatable contact member 27 adapted to engage convolutions of the resistance coils 15 and 16. The spindle 24 also supports a shoe 28 and this shoe is adapted to normally engage and wipe shunt members 29 connected to the walls 9 and 10 by binding posts 30 and 31, and insulated from the reslstance coils 15 and 16, as at 12.

The wall of the casing 5 adjacent the binding posts 18 and 19 is provided with conductors 33 and switch lugs or sockets 34,

ly insulated, and the latter is adapted to be connected to a suitable source of electrical energy.

A and B denote the lamps of the superposed stereopticons 1, and considering the electrical connections, reference will be had to Fig. 6. The lamp A is connected by a wire 35 to the binding post 31 and by a wire 36 to the binding post 19, to which the resistance coil 15 is connected. The lamp A is also connected by-a wire 37 to one of the switch plugs 34 and the same switch plug by a wire 38 to the lamp B.

The lamp B is connected by a wire 39 to one of the shunt members 29 and said wire is connected by a wire 40 to theresistance coil 16.

The yoke 22 is connected by a wire 41 to the other of the switch plugs 34. From the wiring diagram Fig. 6, it will be observed that when the cut-out arm is in an extreme position the path of the current to lamp A 1s throu h its shunt member and lam A thereby urns at full brilliancy, while the path of the current to'lamp B is through its resistance member 16 and lamp B is thereby dinnned. As the cut-out arm 'is moved toward the renter and resistance member 16 is shortened lamp B is gradual] brought to full brilliaucy while the briliancyl of lamp A has not been changed due to the connection which has been maintained through its shunt member. As the cut-out arm or lever is moved from this central position to the extreme left the opposite shunt member will maintain thc full brilliancy of lamp B while the path of the current through the increasing resistance member 15 will radually decrease the brilliancy of lamp This o ration is reversible. We attach considera )le importance to the use of the two shunt members used in conjunction with the two resistance mcmbers.

By using a hollow insulated core, there is sufficient structure for the' windings or convolutions of the resistance coils besides the radiation of heat within the casing which is provided with a series of openings, as shown in Fi 2.

What we clalm is 1. In an electric light dissolving device, resistance coils, a shunt member adjacent to each coil adapted for circuits with lamps, and a switch arm common to said coils and shunt members in circuit with said lamps, adapted to be shifted relative to said colls and shunt members to bridge said shunt members, and adapted for a circuit including either resistance coil.

2. An electric light dissolving device comprising a casing ada ted for attachment to a stereopticon, a ho low insulated core in said casing and insulated therefrom, resistance coils in conjunction with shunt members supported by said core and adapted for circuits with lamps, and a switch arm movable in front of said core adapted for bridging said shunt members and adapted for a circuit including both lamps and a circuit including 'either lamp and either resistance coil.

3. The combination with a stereopticon having lamps, of a casin attached to the stereopticon, an insulated hollow core in the casing, resistance coils in conjunction with shunt members on' said core adapted for with lam s, a yoke shaped switch arm adapted or circuits with the lamps and adapted to swing in front of said core, a rotatable contact member carried by said switch arm adapted to engage either resistance coil, and a shoe carried by said switch arm adapted to bridge said shunt members.

5. The combination with lamps and a suitable sourceA of electrical energy, shunt members in circuit with said lamps, a switch arm adapted to bridge said shunt members and maintain said lamps at Afull brilliancy, and resistance coils in circuit with said lamps and adapted to be independently enaged by said switch arm when the briliancy of either lamp is to be dissolved.

6. The combination with lamps and a suitable source of electrical energy, of shunt members in circuit with said lamps and said source of electrical energy, a switch arm in circuit With said source of electrical energy and which in a central position bridges the shunt members to maintain said lamps at full brilliancy and resistance coils positioned so that movement of said arm in either direction will place either of said resistance coils in circuit with either of said lamps to dissolve the light thereof.

7. The combination of lamps and a suitable source of electrical energy, shunt members in circuit With said lamps, means movable relative to said shunt members adapted to maintain said lamps at full brilliancy, and resistance means adjacent each shunt member and in circuit with said lamps and adapted to be independently engaged by said movable means When the brilliancy of either lamp is to be dissolved.

In testimony whereof we afiix our signa.- tures in presence of two Witnesses.

Witnesses:

ANNA M. DORR, KARL H. BUTLER. 

